the principal concerns of demography in archaeology according to Andrew T. Chamberlain

In seeking to reconstruct the cultures and societies of the past, archaeology primarily investigates the material remnants that survive in the present-day environment. This evidence consists typically of the more robust elements of material culture, supplemented by the organic evidence for past environments and to a lesser extent by the surviving skeletal remains of the people themselves. There is no quick and easy route by which population size and structure can be inferred from these kinds of archaeological data. A multitude of confounding factors, including the differential deposition, preservation and recovery of archaeological remains, conspire to render samples incomplete and unrepresentative, while indirect evidence for population numbers (such as settlement size) is amenable to a variety of conflicting interpretations.However, the following examples outline some of the ways in which demographic models and data can play an importantrole both in underpinning the theoretical basis of archaeology and in aiding the interpretation of particular sites and assemblages. 1.2.2 Population pressure: cause or effect? Qualitative demographic models have frequently played an important role in theoretical archaeology, as they have more widely within social history. Significant increases in population seem to have accompanied major technological advances such as the invention of Upper Palaeolithic bladeindustries (Shennan, 2001), the origins of food production (Hassan, 1973; Bronson, 1975; Cohen, 1977) and the onset of industrialisation in western Europe (McKeown, 1976). One general explanation for these episodic rises in population numbers, presented by Childe (1936) and endorsed by subsequent generations of economic historians and prehistorians, is the neo-Malthusian axiom that under normal circumstances the size of a population approaches an upper limit determined by the availability of introduction 5 critical resources. According to this viewpoint, technological, social and/or ideological change brings about the conditions under which a population is free to expand beyond these restraints until it is limited by a new barrier togrowth. The recurring resource ‘problem’ is solved through a succession of sociocultural innovations, including change in land use, novel patterns of exploitation of resources, technological advance, specialisation, increased economic exchange and so on, enabling the population to periodically increase in size and density. Set against this view is the theory, first articulated by Boserup (1965) and Dumond (1965), and taken up with enthusiasm during the rise of New Archaeology by Binford (1968), Carneiro (1970) and Renfrew (1973), that cultural change is primarily a consequence of population growth rather than a trigger for growth. It is perhaps noteworthy that Boserup’s model not only appealed to Processual Archaeologists as a plausible exemplar of the theorised ecological basis of cultural change, but it also coincided with widerconcerns about the possible economic and social consequences of unconstrained twentieth-century global population growth (Ehrlich, 1968). Population growth has been invoked as a prime mover in prehistoric cultural change, e.g. in the replacement of Neanderthals (Homo neanderthalensis)by anatomically modern Homo sapiens (Zubrow, 1989), in the rapid peopling of the Americas (Martin, 1973) and in the wave of advance model for the spread of agriculture in Europe (Ammerman and Cavalli-Sforza, 1973). Case Study 1.1 Colonisation and population growth in theLate Pleistocene Americas The Americas constitute the last continental land mass to be colonised by humans. This event took place in the Late Pleistocene, and although there is sporadic evidence for earlier settlement the main colonisation event probably occurred towards the end of the last Ice Age and involved the migration of hunter-gatherers into North America from eastern Siberia. The timing and rate of spread of this major colonisation event is controversial, and severallines of evidence have been pursued in order to investigate the early demographic history of the Americas including linguistic diversity amongst present-day native Americans (Nettle, 1999), genetic diversity in modern and ancient native populations (Torroni et al., 1994; Stone and Stoneking, 1999), morphological comparisons amongst human skeletal remains (Jantz and Owsley, 2001), chronological patterning of archaeological sites (Meltzer, 1995) and computer geographical modelling of population dispersal routes (Anderson and Gillam, 2000). The colonisation process in the initial inhabitation of the Americas is believed to have been very rapid, based on the near contemporaneity between the earliest dated Palaeoindian sites in North and South America and the abundance of archaeological sites that emerge acrossNorth America at around 12,000 years BP. The colonisation of an unoccupied space is relatively easy to simulate mathematically, and several authors have generated numerical models that reconstruct the colonisation process. These models, which incorporate high average rates of population growth (increase in numbers of 1% to 3% per annum) and rapid geographical migration (up to 300km per generation),show that the Americas could have been occupied to carrying capacity within 2,000 years starting from a relatively small initial founding population (Young and Bettinger, 1995; Steele et al., 1998; Anderson and Gillam, 2000; Hazlewood and Steele, 2004). The demographic models rely on the assumption that hunter-gatherer populations migrating through unoccupied territory can pursuethe option of long-distance ‘leap-frog’ colonisation movements to ensure that unexploited and productive foraging territory is immediately available forpopulation expansion.

Notes and References

This is a Collected paper from the famous book By Andrew T. Chamberlain